1. Field of the Invention
The present invention relates to a condensate filtering device, especially, a hollow fiber membrane type condensate filtering device to be provided in thermal power plants or nuclear power plants.
Priority is claimed on Japanese Patent Application No. 2007-099638, filed on Apr. 5, 2007, the content of which is incorporated herein by reference.
2. Description of Related Art
A hollow fiber membrane module used in a hollow fiber membrane type condensate filtering device usually has approximately a 5 to 10 year lifetime. In order to determine whether the hollow fiber membrane module can be further used, it is necessary that a part of the hollow fiber membrane is sampled to be a sample and the sample is examined about its properties such as tensile elongation or the like. For examining the properties, conventionally, the following operations are necessary.
(1) A module which is practically being used is taken out of a column by detaching the upper end plate of a condensate filtering device.
(2) A part of a protective outer cylinder of the module is cut to make a window for sampling a hollow fiber membrane, and the window is closed after sampling the hollow fiber membrane.
(3) The upper end plate is attached to the condensate filtering device. All gaskets are changed to new ones.
(4) A pressure/leak test of the condensate filtering device is carried out.
In such a conventional method, in order to open the condensate filtering device, the device is required to be separated from a system during sampling. However, since the condensate filtering device performs important roles of removing suspension materials in a condensate and protecting important devices provided in subsequent stages, sampling cannot be carried out while a power plant is in use and has been substantially carried out while the power plant is being stopped. In order to sample the hollow fiber membrane, a few days and a lot of money are required, and further it is necessary to consider radiation protection of an operator when the condensate filtering device is provided in the radiation controlled area.
In order to know membrane deterioration or the like in a membrane filtering device, a technique such that membrane deterioration or the like of a main body of the membrane filtering device can be simulated by providing a mini-membrane module to the main body of the membrane filtering device in parallel and flowing water to be treated into the mini-membrane module is known (Japanese Unexamined Patent Application No. 2003-340245).
However, the technique disclosed in Japanese Unexamined Patent Application No. 2003-340245 does not direct to a simulation for a condensate filtering device, but directs to a simulation of a clogging state of the membrane of the main body of the membrane filtering device or a simulation for determining the appropriateness of the chemical washing. In the hollow fiber membrane type condensate filtering device to be provided in thermal power plants or nuclear power plants, as described above, the hollow fiber membrane module usually has a 5 to 10 year lifetime, and condensate filtration, air scrubbing washing, discharge of waste water after washing, and an operation for filling the module with water after the washing are repeated for a long period of time. However, Japanese Unexamined Patent Application No. 2003-340245 does not disclose simulations of the above operation modes. When such simulations are applied to the condensate filtering device, it is considered that, especially, simulations of air scrubbing washing and operations accompanied therewith are important. However, such a simulator has not been known.